Articles such as doors, wainscot, paneling, cabinet and other furniture doors, and other building materials were traditionally made of natural wood. Natural wood provides an upscale appearance that is aesthetically desirable to many consumers. Unfortunately, due to the depletion of natural resources, natural wood articles have become expensive and much less commonplace than they once were. Also, natural wood has drawbacks, such as its proneness to warping and rotting. As a consequence, many industries, including the building industry, have largely shifted production to focus on man-made materials, such as wood composite materials, fiberglass composites, and thermoplastics.
Man-made molded articles, particularly in the building industry, are often manufactured and/or post-formed to provide an appearance that simulates that of natural wood because of its desirable and upscale appearance. For example, the exterior (observed) surface of a man-made board may be molded or embossed to provide the appearance and feel of a wood grain. U.S. Pat. Nos. 7,367,166, 7,959,817, and 8,246,339, for example, describe molded door skins (also known as door facings) with small grooves configured and arranged to collectively simulate an appearance of a naturally appearing wood grain tick pattern, as well as tonal portions that simulate darkened naturally occurring wood grain background tone. Additionally, the grain patterns on molded articles, especially door skins, may be arranged to simulate the appearance of horizontal and/or vertical extending planks or boards. Planks extending primarily horizontally, that is, widthwise for most entry door skins, such as typically present at the bottom and top of the exterior surface of the door skin and sometimes referred to as rails, may be provided with horizontal wood tick patterns. Planks extending primarily vertically, that is, lengthwise for most entry door skins, such as typically present at the opposite sides of the exterior surface of the door skin and sometimes referred to as stiles, may be provided with vertical wood tick patterns that are generally perpendicular to the horizontal wood tick patterns of the horizontal planks. The exterior surface may also be provided with molded witness lines (or strike lines) to delineate the horizontal and vertical planks from one another. The exterior surface is often coated with paint, stain, lacquer, and/or a protective layer.
The exterior surface of a molded article, especially a door skin, can also be molded to simulate one or more “inner” panels forming part of the exterior surface. In the case of door skins, the inner panels are typically either coplanar with or recessed from the main body portion of the door skin. However, it may be desirable for certain articles to have the inner panels protruding relative to the main surface portion. Contoured portions surround the inner panels to connect the inner panels to the main body portion of the molded article. The contoured portions may be, for example, concave, convex, linear-sloped, and/or stepped walls. The contoured portions may provide superior aesthetic qualities which may, for example, simulate the attractive milled appearance of a natural wood multi-panel door.
Man-made molded articles of the type described above are often stacked on and nested with one another, that is, exterior face to interior face (or vice versa), in nesting relationship for palletized transportation and storage of the articles. Unstable nesting of such stacked molded articles can cause abrasive rubbing of the molded articles against one another, particularly during transport. More specifically, the abrasive rubbing takes place between the finished exterior surface of one molded article and the unfinished interior surface of another molded article stacked thereon or thereunder. The abrasive rubbing can result in unacceptable levels of damage to the finished exterior surface, such as paint picking, paint burnishing, coating removal, and cracking. Damage to the exterior surface can ruin the finish, devaluing the article or making it commercially unacceptable. To reduce and possibly avoid such surface damage, protective materials such as slip sheets (made of, for example, paper, plastic, etc.) and/or spacers (made of, for example, cardboard) may be placed on each molded article in the stack.
The present inventors have observed that surface damage is particularly pronounced on the exterior surface of the articles having inner panels that are recessed from the main body portion of the article. Paint pricking, paint burnishing, coating removal, and cracking are especially problematic at the inner panel corners and the adjacent corners of the contoured portions of the recessed inner panels. The present inventors surmise that these problems are localized at these corner areas because the corner areas, as the result of the geometry of the inner panels, are rigid relative to the remainder of the skin. The present inventors believe that, unlike other areas of the molded articles, the corner areas of the recessed panels are unable to flex in response to the stack load or stacking shifting during transport and handling.